"It is the responsibility and duty of the ECB to make its own decisions on if it will fulfill its obligations and to tell the ICC of its decision so that the matter can be resolved."

The ECB believes threats to the safety of the England team, contained in a letter purporting to have been sent by the "Sons and Daughters of Zimbabwe" should be taken seriously.

An investigation has been carried out by the South African police, who have judged the letter to be a hoax.

The letter threatens to send the England players "back to Britain in wooden coffins", and also asks "how safe are your families back in the UK?"

England captain Nasser Hussain revealed the issue had reduced some of his team-mates to tears.

He described a team meeting on Sunday as "very emotional, very heated".

If England do boycott the game, they face the prospect of forfeiting the four points available for winning the match and a large fine from the International Cricket Council for failing to fulfil contractual obligations.